Fig. 3. Graphical demonstration of the effects of intravenous lidocaine on the mean neuronal activity of 10 sustained (open circles) and 10 abrupt (filled squares) neurons. (A ) Neuronal activity is quantified as the total number of impulses during the period of colorectal distension (CRD; 80 mmHg, 20 s). (B ) Neuronal activity is quantified as the spontaneous activity in the 10-s period before the onset of CRD. (C ) Neuronal activity is expressed as “evoked” activity, calculated as the total activity minus the ongoing spontaneous activity. All data were normalized as a percentage of the average of the two baseline responses measured before the administration of lidocaine. Bars indicate SD. Times and doses of lidocaine are indicated above and by dotted lines. *P < 0.05 and **P < 0.01, indicating significant reductions in activity from baseline levels of activity.